1. Field of the Invention
The present invention relates to a camera exposure time control device which permits exposure time control in response to the measurement of light reflected from a surface of a shutter curtain and/or a surface of a film.
2. Description of the Prior Art
With this type of exposure time control, if a surface of a first or leading shutter curtain and a surface of a film differ in reflection factor, a difference occurs in the light measurement output around the time when the shutter curtain starts travelling, causing an error in exposure time control. Since it is practically impossible to make the surface of the shutter curtain compatible in reflection factor with surfaces of all films available on the market, a light measurement output requires some correction during exposure control operation to ensure correct exposure time control at all times.
Japanese Patent Laid-Open Publication Nos. Sho 53-46725 and Sho 54-151029, for example, disclose a correction method, in which in addition to a light measuring circuit originally included in an exposure time control circuit is provided another light measuring circuit to detect a difference in reflection factor between a surface of a leading shutter curtain and a surface of a film. However, this method is disadvantageous in that the additional light measuring circuit makes an entire exposure time control circuit complex.